CVE-2016-4121 in Flash Player
Summary
by MITRE
Use-after-free vulnerability in Adobe Flash Player before 18.0.0.352 and 19.x through 21.x before 21.0.0.242 on Windows and OS X and before 11.2.202.621 on Linux allows attackers to execute arbitrary code via unspecified vectors, a different vulnerability than CVE-2016-1097, CVE-2016-1106, CVE-2016-1107, CVE-2016-1108, CVE-2016-1109, CVE-2016-1110, CVE-2016-4108, and CVE-2016-4110.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 01/27/2019
The CVE-2016-4121 vulnerability represents a critical use-after-free flaw in Adobe Flash Player affecting multiple versions across different operating systems. This vulnerability specifically impacts Flash Player versions before 18.0.0.352 and 19.x through 21.x before 21.0.0.242 on Windows and OS X, as well as versions before 11.2.202.621 on Linux. The flaw allows attackers to execute arbitrary code through unspecified vectors, making it a particularly dangerous security issue that could lead to complete system compromise. The vulnerability operates independently from several other related issues including CVE-2016-1097, CVE-2016-1106, CVE-2016-1107, CVE-2016-1108, CVE-2016-1109, CVE-2016-1110, CVE-2016-4108, and CVE-2016-4110, indicating it represents a distinct attack surface that requires specific mitigation approaches.
The technical nature of this use-after-free vulnerability stems from improper memory management within the Flash Player runtime environment. When a Flash application or content is processed, the player allocates memory for objects and resources, but fails to properly validate or manage the lifecycle of these memory segments. This allows an attacker to manipulate the execution flow by creating conditions where freed memory locations are accessed after they have been deallocated, leading to potential code execution. The flaw typically occurs during the processing of malformed or malicious Flash content that triggers the memory management error, enabling attackers to inject and execute arbitrary code with the privileges of the Flash Player process.
The operational impact of CVE-2016-4121 extends beyond simple exploitation, as it represents a significant threat vector for advanced persistent threats and zero-day attacks. Attackers can leverage this vulnerability through drive-by downloads, malicious websites, or compromised web applications that serve malicious Flash content to unsuspecting users. The vulnerability's presence across multiple Flash Player versions and operating systems increases its attack surface considerably, making it particularly attractive to threat actors seeking broad exploitation capabilities. This vulnerability directly maps to CWE-416, which specifically addresses use-after-free conditions in software, and aligns with ATT&CK technique T1059.007 for execution through Flash content, making it a critical target for both defensive and offensive cybersecurity operations.
Mitigation strategies for CVE-2016-4121 primarily focus on immediate patch deployment and operational security measures. Organizations should prioritize updating Adobe Flash Player to versions 18.0.0.352, 21.0.0.242, or 11.2.202.621 respectively for each affected platform, as these versions contain the necessary memory management fixes to prevent the use-after-free condition. Additionally, implementing browser security controls such as disabling Flash content by default, using sandboxing technologies, and deploying web application firewalls can significantly reduce the risk of exploitation. Network-level mitigations including content filtering and monitoring for suspicious Flash-related traffic can provide additional layers of defense. Security teams should also consider implementing automated patch management systems to ensure rapid deployment of security updates across enterprise environments, as the vulnerability's widespread nature makes timely remediation essential for maintaining organizational security posture.